Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government

This map was printed on an electronic plotter directly from digital files. Dimensional calibration may vary between electronic plotters and between X and Y 

directions on the same plotter, and paper may change size due to atmospheric conditions; therefore, scale and proportions may not be true on plots of this 

map.

For sale by U.S. Geological Survey, Information Services, Box 25286, Federal Center, Denver, CO 80225, 1–888–ASK–USGS

Digital files available at http://pubs.usgs.gov/sim/3302/

Suggested Citation: Phillips, E.L., Erdey, M.D., and Cochrane, G.R., 2014, Seafloor character, Offshore of Coal Oil Point map area, California, sheet 5 in Johnson, 

S.Y., Dartnell, P., Cochrane, G.R., Golden, N.E., Phillips, E.L., Ritchie, A.C., Kvitek, R.G., Dieter, B.E., Conrad, J.E., Lorenson, T.D., Krigsman, L.M., Greene, H.G., 

Endris, C.A., Seitz, G.G., Finlayson, D.P., Sliter, R.W., Wong, F.L., Erdey, M.D., Gutierrez, C.I., Leifer, I., Yoklavich, M.M., Draut, A.E., Hart, P.E., Hostettler, F.D., 

Peters, K.E., Kvenvolden, K.A., Rosenbauer, R.J., and Fong, G. (S.Y. Johnson and S.A. Cochran, eds.), California State Waters Map Series—Offshore of Coal Oil 

Point, California: U.S. Geological Survey Scientific Investigations Map 3302, pamphlet 57 p., 12 sheets, scale 1:24,000, http://dx.doi.org/10.3133/sim3302.

ISSN 2329-132X (online)

http://dx.doi.org/10.3133/sim3302

US Army Corps

of Engineers

Figure 6. Rugosity (characterization of roughness derived from bathymetry) draped over shaded-relief bathymetry 

(see sheet 2) for same area as figure 4 (Box B on map). Rugosity values are displayed in muted “rainbow” color 

spectrum that ranges from purple (low rugosity) through green (medium rugosity) to red (high rugosity). Areas of 

moderate slope are indicated by medium-rugosity values (green); areas of low slope, by low-rugosity values 

(purple). Interpreted substrate classes from figure 4 included for comparison. Bathymetric contour (100 m) added 

for depth reference. 

Fine- to medium-grained smooth sediment;

 Depth Zone 3, Slope Class 1

Rock and boulder, rugose;

Depth Zone 3, Slope Class 1

Mixed smooth sediment and rock;

Depth Zone 3, Slope Class 1 

Fine- to medium-grained 

smooth sediment; 

Depth Zone 3, Slope Class 2

Mixed smooth sediment 

and rock; Depth Zone 3, 

Slope Class 2 

Rock and boulder, 

rugose; Depth Zone 4, 

Slope Class 2

Mixed smooth sediment 

and rock; Depth Zone 4, 

Slope Class 2 

Rock and boulder, 

rugose; Depth Zone 3, 

Slope Class 2

100 m

Figure 5. Acoustic-backscatter image (see sheet 3) draped over shaded-relief bathymetry (see sheet 2) for same 

area as figure 4 (Box B on map). Brighter areas indicate coarse-grained, rough, or hard seafloor; darker areas 

indicate unconsolidated (loosely packed) sediment. Interpreted substrate classes from figure 4 included for 

comparison. Bathymetric contour (100 m) added for depth reference.

Fine- to medium-grained smooth sediment;

 Depth Zone 3, Slope Class 1

Rock and boulder, rugose;

Depth Zone 3, Slope Class 1

Mixed smooth sediment and rock;

Depth Zone 3, Slope Class 1 

Fine- to medium-grained 

smooth sediment; 

Depth Zone 3, Slope Class 2

Mixed smooth sediment 

and rock; Depth Zone 3, 

Slope Class 2 

Rock and boulder, 

rugose; Depth Zone 4, 

Slope Class 2

Mixed smooth sediment 

and rock; Depth Zone 4, 

Slope Class 2 

Rock and boulder, 

rugose; Depth Zone 3, 

Slope Class 2

100 m

Figure 4. Detailed view of substrate classes mapped further offshore, southwest of Naples (see Box B, on map, for 

location): Depth Zone 3 (30 to 100 m), Depth Zone 4 (100 to 200 m), Slope Class 1 (0°–5°), and Slope Class 2 (5°–30°). 

Fine- to medium-grained smooth sediment is shown in shades of green; mixed smooth sediment and rock is shown 

in shades of tan and orange; and rugose rock and boulders are shown in shades of red and brown. Bathymetric 

contour (100 m) added for depth reference. Note that pixel size increases in areas where 5-m-resolution 

bathymetry was collected (in water deeper than 80 m).

Fine- to medium-grained smooth sediment;

 Depth Zone 3, Slope Class 1

Rock and boulder, rugose;

Depth Zone 3, Slope Class 1

Mixed smooth sediment and rock;

Depth Zone 3, Slope Class 1 

Fine- to medium-grained 

smooth sediment; 

Depth Zone 3, Slope Class 2

Mixed smooth sediment 

and rock; Depth Zone 3, 

Slope Class 2 

Rock and boulder, 

rugose; Depth Zone 4, 

Slope Class 2

Mixed smooth sediment 

and rock; Depth Zone 4, 

Slope Class 2 

Fine- to medium-grained

smooth sediment;

Depth Zone 4, 

Slope Class 2

Rock and boulder, 

rugose; Depth Zone 3, 

Slope Class 2

100 m

BOX B

Mixed smooth sediment and rock;

 Depth Zone 2, Slope Class 1 

Rock and boulder, rugose;

Depth Zone 2, Slope Class 1

Fine- to medium-grained 

smooth sediment;

Depth Zone 2, Slope Class 1

Figure 3. Rugosity (characterization of roughness derived from bathymetry) draped over shaded-relief bathymetry 

(see sheet 2) for same area as figure 1 (Box A on map). Rugosity values are displayed in muted “rainbow” color 

spectrum that ranges from purple (low rugosity) through green (medium rugosity) to red (high rugosity). Areas of 

high slope are indicated by high-rugosity values (red); areas of low slope, by medium- to low-rugosity values (green 

to purple); however, northwest-southeast-trending areas of high rugosity are data-collection artifacts, as are gray 

areas surrounding data gaps in lower right. Interpreted substrate classes from figure 1 included for comparison. 

Mixed smooth sediment and rock;

 Depth Zone 2, Slope Class 1 

Rock and boulder, rugose;

Depth Zone 2, Slope Class 1

Fine- to medium-grained 

smoothsediment;

Depth Zone 2, Slope Class 1

Figure 2. Acoustic-backscatter image (see sheet 3) draped over shaded-relief bathymetry (see sheet 2) for same 

area as figure 1 (Box A on map). Brighter areas indicate coarse-grained, rough, or hard seafloor; darker areas 

indicate unconsolidated (loosely packed) sediment. Interpreted substrate classes from figure 1 included for 

comparison.

Mixed smooth sediment and rock;

 Depth Zone 2, Slope Class 1 

Rock and boulder, rugose;

Depth Zone 2, Slope Class 1

Fine- to medium-grained 

smooth sediment;

Depth Zone 2, Slope Class 1

Figure 1. Detailed view of substrate classes mapped in shallow nearshore, just south of Naples (northwest of Coal 

Oil Point; see Box A, on map, for location): Depth Zone 2 (intertidal to 30 m), and Slope Class 1 (0°–5°). Fine- to 

medium-grained smooth sediment is shown in shades of green; mixed smooth sediment and rock is shown in 

shades of tan; and rugose rock and boulders are shown in shades of pink. White areas in lower right are data 

gaps.

BOX A

Fine- to medium-grained

smooth sediment;

Depth Zone 4, 

Slope Class 2

Fine- to medium-grained

smooth sediment;

Depth Zone 4, 

Slope Class 2

0.4 0.1 Rock and 

boulder, rugose 0.3 0.1 0.1

5.8

0.1

<0.1 <0.1

5.3

<0.1 <0.1

Mixed smooth

sediment and rock 1.0 1.1 1.8 1.9

Fine- to mediumgrained smooth

sediment

94.3 102.6 15.3 16.7 71.7 78.0

0.1 0.2

2.5 2.8

7.3 8.0

Total

percent percent of total sq km sq km percent of total sq km percent of total sq km

<0.1

<0.1 0.0 <0.1 <0.1 0.0 0.0

<0.1

<0.1 0.0

0.0 0.0

Anthropogenic,

smooth, hard

(scours, coarse

sediment)

Anthropogenic,

rugged (pipe)

Depth Zone 2

(water depth 0–30 m)

Depth Zone 3

(water depth 30–100 m)

Depth Zone 4

(water depth 100–200 m)

Table 1. Coverage of classified seafloor, in square kilometers (sq km) and percent of total area, broken into 

California Marine Life Protection Act Depth Zones 2, 3, and 4.

CALIF.

0 4 8 Nautical Miles

Kilometers 0 5 10

120° 119°40' 119°20' 119°

34°

34°20'

MAP LOCATION

Ventura

Santa Barbara

Anacapa

Island

Santa Cruz Island Santa Rosa Island

Area of

Map

Santa Barbara Channel

Limit of California’s

State Waters

DISCUSSION

This seafloor-character map of the Offshore of Coal Oil Point map area in southern California was 

produced using video-supervised, maximum-likelihood classification of the bathymetry and backscatter 

(intensity of return) signals from sonar systems (a summary of the video data collected for the purpose of 

supervising the classification is shown on sheet 6). Rugosity (a GIS-derived characterization of roughness) 

and backscatter intensity were used as variants in the classification. The interpreted classifications were then 

draped over shaded-relief bathymetry (see sheet 2).

The substrate classes mapped in this area have been divided into the following California Marine Life 

Protection Act depth zones: Depth Zone 2 (intertidal to 30 m), Depth Zone 3 (30 to 100 m), and Depth Zone 

4 (100 to 200 m). In addition, the following slope classes are represented on this map (Coastal and Marine 

Ecological Classification Standard slope zone is shown in parentheses): Slope Class 1, 0° to 5° (flat); Slope 

Class 2, 5° to 30° (sloping); and Slope Class 3, 30° to 60° (steeply sloping). Depth Zone 1 (intertidal), Depth 

Zone 5 (greater than 200 m), and Slope Class 4, 60° to 90° (vertical), are not present in this map area. 

Fine- to medium-grained smooth sediment (sand and mud) makes up 94.3 percent (102.6 km2

) of the 

map area: 16.7 km2

 is in Depth Zone 2, 78.0 km2

 is in Depth Zone 3, and 8.0 km2

 is in Depth Zone 4. Mixed 

smooth sediment (sand and gravel) and rock (sediment typically forming a veneer over bedrock, or rock 

outcrops with little to no relief) make up 5.3 percent (5.8 km2

) of the map area: 1.1 km2

 is in Depth Zone 2, 

1.9 km2

 is in Depth Zone 3, and 2.8 km2

 is in Depth Zone 4. Rock and boulder, rugose (rock outcrops and 

boulder fields having high surficial complexity) makes up 0.3 percent (0.4 km2

) of the map area: 0.1 km2

 is 

in Depth Zone 2, 0.1 km2

 is in Depth Zone 3, and 0.2 km2

 is in Depth Zone 4. Rugged anthropogenic 

material includes a pipe in Depth Zone 2 and hard material associated with oil-platform structural foundation 

in Depth Zone 3; together they make up less than 0.1 percent (<0.1 km2

) of the map area. Smooth, hard 

anthropogenic material (scours; also, coarse sediment surrounding oil platforms), present only in Depth Zone 

3, makes up less than 0.1 percent (<0.1 km2

) of the map area (table 1).

DESCRIPTION OF MAP UNITS

DEPTH ZONE 2—INTERTIDAL TO 30 METERS WATER DEPTH

SLOPE CLASS 1—0 TO 5 DEGREES

Fine- to medium-grained smooth sediment—Low backscatter, low rugosity; typically mud to 

medium-grained sand; often rippled and (or) burrowed

Mixed smooth sediment and rock—Moderate to very high backscatter, low rugosity; typically 

coarse-grained sand, gravel, cobbles, and bedrock

Rock and boulder, rugose—High backscatter, high rugosity; typically boulders and rugose 

bedrock

Rugged anthropogenic material—High backscatter, high rugosity; related to development by 

humans

SLOPE CLASS 2—5 TO 30 DEGREES

Fine- to medium-grained smooth sediment—Low backscatter, low rugosity; typically mud to 

medium-grained sand; often rippled and (or) burrowed

Mixed smooth sediment and rock—Moderate to very high backscatter, low rugosity; typically 

coarse-grained sand, gravel, cobbles, and bedrock

Rock and boulder, rugose—High backscatter, high rugosity; typically boulders and rugose 

bedrock

DEPTH ZONE 3—30 METERS TO 100 METERS WATER DEPTH

SLOPE CLASS 1—0 TO 5 DEGREES

Fine- to medium-grained smooth sediment—Low backscatter, low rugosity; typically mud to 

medium-grained sand; often rippled and (or) burrowed

Mixed smooth sediment and rock—Moderate to very high backscatter, low rugosity; typically 

coarse-grained sand, gravel, cobbles, and bedrock

Rock and boulder, rugose—High backscatter, high rugosity; typically boulders and rugose 

bedrock

Smooth, hard anthropogenic material—High backscatter, low rugosity; related to development 

by humans

Rugged anthropogenic material—High backscatter, high rugosity; related to development by 

humans 

SLOPE CLASS 2—5 TO 30 DEGREES

Fine- to medium-grained smooth sediment—Low backscatter, low rugosity; typically mud to 

medium-grained sand; often rippled and (or) burrowed

Mixed smooth sediment and rock—Moderate to very high backscatter, low rugosity; typically 

coarse-grained sand, gravel, cobbles, and bedrock

Rock and boulder, rugose—High backscatter, high rugosity; typically boulders and rugose 

bedrock

DEPTH ZONE 4—100 METERS TO 200 METERS WATER DEPTH

SLOPE CLASS 1—0 TO 5 DEGREES

Fine- to medium-grained smooth sediment—Low backscatter, low rugosity; typically mud to 

medium-grained sand; often rippled and (or) burrowed

Mixed smooth sediment and rock—Moderate to very high backscatter, low rugosity; typically 

coarse-grained sand, gravel, cobbles, and bedrock

SLOPE CLASS 2—5 TO 30 DEGREES

Fine- to medium-grained smooth sediment—Low backscatter, low rugosity; typically mud to 

medium-grained sand; often rippled and (or) burrowed

Mixed smooth sediment and rock—Moderate to very high backscatter, low rugosity; typically 

coarse-grained sand, gravel, cobbles, and bedrock

Rock and boulder, rugose—High backscatter, high rugosity; typically boulders and rugose 

bedrock

SLOPE CLASS 3—30 TO 60 DEGREES

Mixed smooth sediment and rock—Moderate to very high backscatter, low rugosity; typically 

coarse-grained sand, gravel, cobbles, and bedrock

EXPLANATION OF MAP SYMBOLS

Area of “no data”—Areas near shoreline not mapped owing to insufficient high-resolution 

seafloor mapping data; areas beyond 3-nautical-mile limit of California’s State Waters were 

not mapped as part of California Seafloor Mapping Program

3-nautical-mile limit of California’s State Waters

Seafloor Character, Offshore of Coal Oil Point Map Area, California

By

Eleyne L. Phillips, Mercedes D. Erdey, and Guy R. Cochrane

2014

ONE MILE = 0.869 NAUTICAL MILES

1 .5 0 1 KILOMETER

1000 0 1000 2000 3000 4000 5000 6000 7000 FEET

1 1/2 0 1 MILE

SCALE 1:24 000

APPROXIMATE MEAN

DECLINATION, 2014

MAGNETIC NORTH

12 / ° 1 2

TRUE NORTH

Onshore elevation data from NOAA Coastal Services Center (data collected by 

EarthData International in 2002-2003) and from U.S. Army Corps of Engineers (data 

collected by Fugro Pelagos in 2009). Offshore shaded-relief bathymetry from map on 

sheet 2, this report. California's State Waters limit from NOAA Office of Coast Survey

Universal Transverse Mercator projection, Zone 11N

NOT INTENDED FOR NAVIGATIONAL USE

Seafloor character mapped by Eleyne L. Phillips and Guy R. Cochrane, 2011 

GIS database and digital cartography by Eleyne L. Phillips and Mercedes D. 

Erdey

Edited by Taryn A. Lindquist

Manuscript approved for publication June 2, 2014

BOX A

BOX B Goleta Point

Coal Oil Point

Isla Vista

Goleta

 Naples

120° 119°55' 119°50'

120° 119°55' 119°50'

34°25'

34°25'

34°30'

Scientific Investigations Map 3302

Sheet 5 of 12

Pamphlet accompanies map

U.S. Department of the Interior

U.S. Geological Survey